In prior work we have been investigating the selective processes in visual perception by which one stimulus is encoded and/pr reported from among a number of equally potent stimuli. The basic experimental tecnique presents simultaneously a visual display containing a circular arrangement of letters with a line indicator designating the target letter that the S is to report. Results so far have indicated the general time required for the programming of stimulus selection and the effects of noise or irrelevant signals. Most importantly, it has been demonstrated that selective attention cannot eliminate completely the effect of noise stimuli. Rather, there appears to be a minimal channel size beyond which attention cannot be restricted. This minimal capacity may be of a spatial extent in the visual field or an information capacity minimum. Further, it has been found that irrelevant stimuli exert their interfering effects not through input processing but through response encoding or competition. Further research is proposed to further delineate the characteristics of selective attention in vision, particularly in terms of a) selection time; b) capacity or spatial character; and c) effectiveness of basic visual dimensions for selection. A conception of attention as an aggregate of processing channels, differing in speed and/or capacity, will be explored.